Microwave plasma processing apparatus and microwave supplying method

ABSTRACT

Disclosed is a microwave plasma processing apparatus including: a processing container configured to define a processing space; a microwave generator configured to generate microwaves; a distributor configured to distribute the microwaves to a plurality of waveguides; an antenna installed in the processing container and to radiate the microwaves distributed to the plurality of waveguides to the processing space; a monitor unit configured to monitor a voltage of each of the plurality of waveguides; a storage unit configured to store a difference between a monitor value of the voltage monitored by the monitor unit and a predetermined reference value of the voltage and a control value of a distribution ratio of the distributor corresponding to the difference; and a control unit configured to acquire the control value of the distribution ratio of the distributor from the storage unit and to control the distribution ratio of the distributor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/326,649, filed on Jul. 9, 2014, which claims priority from JapanesePatent Application No. 2013-145045, filed on Jul. 10, 2013 with theJapan Patent Office, all of which are incorporated herein in theirentireties by reference.

TECHNICAL FIELD

Various aspects and exemplary embodiments disclosed herein relate to amicrowave plasma processing apparatus and a microwave supplying method.

BACKGROUND

A microwave plasma processing apparatus known in the related art useshigh density plasma excited by a microwave electric field. For example,the microwave plasma processing apparatus has a processing containerconfigured to plasma-process a substrate to be processed, a microwavegenerator configured to generate microwaves to generate plasma of aprocessing gas in the processing container, and a waveguide configuredto guide the microwave generated by the microwave generator into theprocessing container. Further, the microwave plasma processing apparatusincludes a planar antenna having a plurality of slots that transmit themicrowaves guided by the waveguide. In the microwave plasma processingapparatus, the microwaves are radiated into the processing containerfrom the slot antenna and the processing gas in the processing containeris deionized to excite the plasma.

However, in such a microwave plasma processing apparatus, it isrequested that the plasma excited by the microwaves be uniformlydistributed in processing space of the processing container in order toensure uniform plasma processing of the entire processed surface of aworkpiece. In this regard, there is a known technology in which adistributor is installed at a rear end side of the microwave generatorto distribute the microwaves from the microwave generator to a pluralityof waveguides by the distributor at a predetermined distribution ratioand radiate the distributed microwaves to a center side and a peripheryside of the processing space from the antenna. See, for example,Japanese Patent Laid-Open Publications Nos. H9-63793, H3-191074, and2007-213994.

SUMMARY

In an exemplary embodiment, a microwave plasma processing apparatusdisclosed herein includes a processing container configured to define aprocessing space; a microwave generator configured to generatemicrowaves for generating plasma of a processing gas introduced into theprocessing space; a distributor configured to distribute the microwavesto a plurality of waveguides; an antenna installed in the processingcontainer and to radiate the microwaves distributed to the plurality ofwaveguides by the distributor, to the processing space; a monitor unitconfigured to monitor a voltage of each of the plurality of waveguides;a storage unit configured to store a difference between a monitor valueof the voltage monitored by the monitor unit and a predeterminedreference value of the voltage and a control value of a distributionratio of the distributor corresponding to the difference; and a controlunit configured to acquire the control value of the distribution ratioof the distributor, which corresponds to the difference between themonitor value of the voltage monitored by the monitor unit and thepredetermined reference value of the voltage, from the storage unit andto control the distribution ratio of the distributor based on theacquired control value thereby distributing the microwaves to theplurality of waveguides of the antenna.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, exemplaryembodiments, and features described above, further aspects, exemplaryembodiments, and features will become apparent by reference to thedrawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of an external configurationof a microwave plasma processing apparatus according to a firstexemplary embodiment.

FIG. 2 is a view illustrating an example of an internal configuration ofthe microwave plasma processing apparatus according to the firstexemplary embodiment.

FIG. 3 is a table illustrating an example of information stored by astorage unit in the first exemplary embodiment.

FIG. 4 is a front view illustrating a slot antenna according to thefirst exemplary embodiment.

FIG. 5 is a perspective view illustrating the slot antenna when the slotantenna is viewed from an upper side.

FIG. 6 is a perspective view illustrating the slot antenna when the slotantenna is viewed from a lower side.

FIG. 7 is a cross-sectional view illustrating an example of a detailedconfiguration of the slot antenna in the first exemplary embodiment.

FIG. 8 is a cross-sectional view illustrating a portion of thecross-sectional view of the slot antenna illustrated in FIG. 7 in anenlarged scale.

FIG. 9 is a cross-sectional view illustrating a portion of thecross-sectional view of the slot antenna illustrated in FIG. 7 in anenlarged scale.

FIG. 10 is a perspective view illustrating an example of theintermediate metal body in the first exemplary embodiment which isviewed from the dielectric window side.

FIG. 11 is a perspective view illustrating an example of theintermediate metal body in the first exemplary embodiment which isviewed from the cooling plate side.

FIG. 12 is a view illustrating a processing gas supply path and amicrowave waveguide formed in the slot antenna in the first exemplaryembodiment.

FIG. 13 is a perspective view illustrating a relationship of theintermediate metal body, the inner slow-wave plate, and the outerslow-wave plate in the first exemplary embodiment which is viewed fromthe dielectric window side.

FIG. 14 is a perspective view illustrating a relationship of theintermediate metal body, the inner slow-wave plate, and the outerslow-wave plate in the first exemplary embodiment which is viewed fromthe cooling plate side.

FIG. 15 is a flowchart illustrating an example of a flow of a plasmasupplying method according to the first exemplary embodiment.

FIG. 16 is a diagram illustrating an example of an externalconfiguration of Modified Example 1 of the microwave plasma processingapparatus according to the first exemplary embodiment.

FIG. 17 is a diagram illustrating one example of an externalconfiguration of Modified Example 2 of the microwave plasma processingapparatus according to the first exemplary embodiment.

FIG. 18 is a diagram illustrating an example of an externalconfiguration of Modified Example 3 of the microwave plasma processingapparatus according to the first exemplary embodiment.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The exemplaryembodiments described in the detailed description, drawing, and claimsare not meant to be limiting. Other exemplary embodiments may beutilized, and other changes may be made, without departing from thespirit or scope of the subject matter presented here.

In the aforementioned technology, the microwave distribution ratio isfixed in the distributor. Thus, the distribution uniformity of plasmaexcited by microwaves may be impaired in the processing space of theprocessing container.

According to an exemplary embodiment of the disclosed microwave plasmaprocessing apparatus disclosed herein, the distribution uniformity ofplasma excited by microwaves can be maintained.

Hereinafter, exemplary embodiments of the microwave plasma processingapparatus disclosed herein will be described in detail with reference tothe accompanying drawings. Meanwhile, the present disclosure is notlimited by the exemplary embodiments. The exemplary embodiments may beproperly combined with each other without making processing contentsthereof contradictory.

First Exemplary Embodiment

In an exemplary embodiment, a microwave plasma processing apparatus of afirst exemplary embodiment includes: processing container configured todefine a processing space; a microwave generator configured to generatemicrowaves for generating plasma of a processing gas introduced into theprocessing space; a distributor configured to distribute the microwavesto a plurality of waveguides; an antenna installed in the processingcontainer to seal the processing space and to radiate the microwavesdistributed to the plurality of waveguides by the distributor, to theprocessing space; a monitor unit configured to monitor a voltage of eachof the plurality of waveguides; and a control unit configured to acquirea control value of a distribution ratio of the distributor, whichcorresponds to a difference between a monitor value of the voltagemonitored by the monitor unit and a predetermined reference value of thevoltage, from a storage unit that stores the difference and the controlvalue of the distribution ratio of the distributor corresponding to thedifference to correspond to each other. The control unit is alsoconfigured to control the distribution ratio of the distributor, basedon the acquired control value.

In an exemplary embodiment, the microwave plasma processing apparatus ofthe first exemplary embodiment further includes: a phase shifterinstalled in a specific waveguide of at least one of the plurality ofwaveguides to shift a phase of a voltage of the specific waveguide by aset shift amount. Apart from the control of the distribution ratio ofthe distributor, the control unit properly controls the phase of thevoltage of the specific waveguide and phases of voltages of waveguidesother than the specific waveguide among the plurality of waveguidesusing the monitor value of the voltage monitored by the monitor unit soas to control the shift amount of the phase shifter such that the phasesbecome inverse phases in a dielectric window below the antenna.

In an exemplary embodiment, the microwave plasma processing apparatus ofthe first exemplary embodiment further includes a waveguide guiding themicrowave generated by the microwave generator to the distributor, and atuner installed in the waveguide to match impedance at the microwavegenerator side and impedance of the antenna side.

In an exemplary embodiment, the microwave plasma processing apparatus ofthe first exemplary embodiment is provided with a plurality of sets ofprocessing containers and the antennas. The distributor distributesmicrowaves to the plurality of waveguides corresponding to the pluralityof sets of processing containers and antennas, respectively. The antennaradiates the microwaves distributed to each of the plurality ofwaveguides by the distributor to the processing space of the processingcontainer combined with the antenna. The control unit controls thedistribution ratio of the distributor based on the control valueacquired from the storage unit.

In an exemplary embodiment, the microwave plasma processing apparatus isprovided with a plurality of distributors. The plurality of distributorsdistribute the microwaves generated by the microwave generator to theplurality of waveguides stepwise sequentially. For each distributor, thestorage unit stores the difference and a control value of thedistribution ratio of the distributor corresponding to the difference tocorrespond to each other. The control unit individually controls thedistribution ratio of each of the plurality of distributors based on thecontrol value acquired from the storage unit.

In addition, a microwave supplying method according to the firstexemplary embodiment uses a microwave plasma processing apparatusincluding: a processing container configured to defined a processingspace; a microwave generator configured to generate microwaves forgenerating plasma of a processing gas introduced into the processingspace; a distributor configured to distribute the microwaves to aplurality of waveguides; and an antenna installed in the processingcontainer so as to seal the processing space and to radiating, to theprocessing space, the microwaves distributed to the plurality ofwaveguides by the distributor. The method includes: monitoring a voltageof each of the plurality of waveguides; acquiring a control value of adistribution ratio of the distributor corresponding to a differencebetween a monitor value of the monitored voltage and a predeterminedreference value of the voltage from a storage unit which stores thedifference and the control value of the distribution ratio of thedistributor corresponding to the difference to correspond to each other;and controlling the distribution ratio of the distributor based on theacquired control value.

(Microwave Plasma Processing Apparatus According to First ExemplaryEmbodiment)

FIG. 1 is a diagram illustrating one example of an externalconfiguration of a microwave plasma processing apparatus according to afirst exemplary embodiment. FIG. 2 is a view illustrating an example ofan internal configuration of the microwave plasma processing apparatusaccording to the first exemplary embodiment. Meanwhile, in FIG. 2, apart of the microwave plasma processing apparatus is omitted for theconvenience of description.

As illustrated in FIGS. 1 and 2, the microwave plasma processingapparatus 10 includes a processing container 100, a microwave generator400, a distributor 500, a slot antenna 200, and a dielectric window 300.Further, the microwave plasma processing apparatus 10 includes, in theprocessing container 100, a support 101 on which a substrate W ismounted and a gas shower 102 configured to supply a processing gas intothe processing container 100 from a gas supply source (not illustrated)through an opening 102A.

The processing container 100 defines a processing space S configured toperform a plasma processing on the substrate W placed on the support101. In addition, the processing container 100 is formed with an opening103 connected to an exhaust system such as a vacuum pump.

The microwave generator 400 generates microwaves for generating plasmaof the processing gas supplied to the processing space S. Specifically,the microwave generator 400 includes a magnetron 402, in which when themagnetron 402 is oscillated in a state where a voltage is appliedbetween negative and positive poles, microwaves are generated. Awaveguide 602 is connected to the microwave generator 400 to connect themicrowave generator 400 and the distributor 500. The waveguide 602 isconnected to the distributor 500 to guide the microwave generated by themicrowave generator 400 to the distributor 500.

An isolator 604, a directional coupler 606, and a tuner 608 areinstalled in the waveguide 602. In the isolator 604, reflected waves ofthe microwaves from the slot antenna 200 are separated by a circulatorand the separated reflected waves are converted into heat by a dummyload. The directional coupler 606 branches a part of travelling wavesand reflected waves of the microwaves and outputs the branched waves toa detector 610. The detector 610 converts the microwaves input from thedirectional coupler 606 into an analog signal and outputs the analogsignal to the microwave generator 400. The analog signal output to themicrowave generator 400 is used to control oscillation of the magnetron402 of the microwave generator 400.

The tuner 608 matches impedance at the microwave generator 500 side andimpedance at the slot antenna 200 side. The microwaves generated by themicrowave generator 400 are propagated in the waveguide 602 and guidedto the distributor 500, through the isolator 604, the directionalcoupler 606, and the tuner 608.

The distributor 500 distributes the microwaves input from the waveguide602 to a plurality of waveguides. In the exemplary embodiment, thedistributor 500 distributes the microwaves input from the waveguide 602to two waveguides 612, 613. For example, the distributor 500 has aT-shaped waveguide which includes one input port and two output ports.When a position of a movable short-circuit plate installed in theT-shaped waveguide is moved, the microwaves input o the input port fromthe waveguide 602 are distributed to two waveguides 612, 613. Further, adistribution ratio used for the distribution of the microwaves by thedistributor 500 is variable. A control value of the distribution ratioof the distributor 500 is input by, for example, a control unit 708 tobe described below. That is, the distributor 500 distributes themicrowaves input from the waveguide 602 to two waveguides 612, 613 byusing the control value of the distribution ratio input by the controlunit 708.

The slot antenna 200 is installed in the processing container 100 toseal the processing space S. The dielectric window 300 is installed on aprocessing container 100 side surface of the slot antenna 200. The slotantenna 200 has therein an inner waveguide and an outer waveguide whichare two independent waveguides for transmitting microwaves. The innerwaveguide and the outer waveguide are connected to the two waveguides612, 613, respectively. The slot antenna 200 transmits the microwavedistributed to the two waveguides 612, 613 by the distributor 500 to thedielectric window 300 through the inner waveguide and the outerwaveguide, and radiates the transmitted microwaves to the processingspace S through the dielectric window 300. The microwave radiated to theprocessing space S from the slot antenna 200 deionizes the processinggas supplied to the processing space S to excite plasma of theprocessing gas. An example of an overall configuration of the slotantenna 200 will be described below.

The microwave plasma processing apparatus 10 includes a storage unit702, a monitor unit 704, a phase shifter 706, and a control unit 708, asillustrated in FIG. 1.

The storage unit 702 stores a monitor difference which is a differencebetween a monitor value of a voltage of each of the two waveguides 612,613 which are distribution targets of the microwaves by the distributor500 and a predetermined reference value of the voltage, and the controlvalue of the distribution ratio of the distributor 500 corresponding tothe monitor difference such that the monitor difference and the controlvalue correspond to each other. FIG. 3 is a table illustrating anexample of information stored by the storage unit in the first exemplaryembodiment. For example, as illustrated in FIG. 3, the storage unit 702stores monitor differences and control values to correspond to eachother. Each monitor difference refers to a monitor difference which is adifference between a monitor value of a voltage of each of the twowaveguides 612, 613 which are the distribution targets of the microwavesby the distributor 500 and a predetermined reference value of thevoltage. Each control value refers to a control value of thedistribution ratio of the distributor 500 corresponding to the monitordifference. For example, the storage unit 702 stores a monitordifference “D1” and a control value “C1” to correspond to each other.Further, the storage unit 702 stores a monitor difference “D2” and acontrol value “C2” to correspond to each other.

The monitor unit 704 monitors the voltage of each of the two waveguides612, 213 using voltage sensors 622, 623 which are installed in twowaveguides 612, 613, respectively, and outputs, to the control unit 708,a monitor value which is a detection result of a standing wave in thewaveguide by monitoring the voltage of each of the two waveguides 612,613. Here, monitor values, which are monitored by the monitor unit 704,may include, for example, Vpp which is a peak to peak value of voltageor Vdc which is an intermediate value of voltage. Vpp represents themagnitude of the standing wave generated in the waveguide and Vdcrepresents an offset amount of the standing wave generated in thewaveguide.

The phase shifter 706 is installed in one waveguide 613 of the twowaveguides 612, 613 and shifts the phase of the voltage of the waveguide613 by a set shift amount. Further, the shift amount set in the phaseshifter 706 is controlled by the control unit 708.

The control unit 708 acquires from the monitor unit 704 the monitorvalue of the voltage of each of the two waveguides 612, 613 which ismonitored by the monitor unit 704. The control unit 708 calculates themonitor difference which is the difference between a monitor value and areference value of the voltage of each of the two waveguides 612, 613.The reference value is input from, for example, an input interface (notillustrated) as a recipe requirement. Here, the control unit 708 maycalculate, as the monitor difference, a difference between a monitorvalue and one reference value of the voltage of any one waveguide of thetwo waveguides 612, 613. Further, the control unit 708 may obtain anaverage value of the monitor values of the respective voltages of twowaveguides 612, 613 and calculate a difference between the obtainedaverage value and one reference value as the monitor difference.Further, the control unit 708 may obtain a ratio of the monitor valuesof the respective voltages of the two waveguides 612, 613 and calculatea difference between the obtained ratio and one reference value as themonitor difference. In addition, the control unit 708 acquires, from thestorage unit 702, the control value of the distribution ratio of thedistributor 500 corresponding to the calculated monitor difference, andcontrols the distribution ratio of the distributor 500 based on theacquired control value. For example, when the monitor difference is“D1”, the control unit 708 acquires the control value “C1” from thestorage unit 702 and outputs the acquired control value to thedistributor 500.

Using the monitor values of the respective voltages of the twowaveguides 612, 613, the control unit 708 controls the shift amount ofthe phase shifter 706 such that a phase of the voltage of the waveguide612 and a phase of the voltage of the waveguide 613 are inverted to eachother. That is, the control unit 708 properly sets the phase of thevoltage of the waveguide 612 and the phase of the voltage of thewaveguide 613 to offset the microwaves transmitted to a center side anda peripheral edge side of the dielectric window 300 from the twowaveguides 612, 613 through the inner waveguide and the outer waveguidein the slot antenna 200 with the inverse phases.

Here, an example of the entire configuration of the slot antenna 200illustrated in FIGS. 1 and 2 will be described. FIGS. 4 to 6 illustratean entire external appearance of an example of a slot antenna in thefirst exemplary embodiment. In the example illustrated in FIGS. 4 to 6,the dielectric window 300 is not illustrated for the convenience ofdescription. As illustrated in FIGS. 4 to 6, the slot antenna 200includes a coaxial waveguide 201, a cooling plate 202, a slot antennaplate 203, a gas supply hole 204 configured to supply a processing gasto the inside of the processing container 100, cooling tubes 205, 206configured to cool the coaxial waveguide 201, and a gas inlet hole 207through which the processing gas is supplied to the slot antenna 200.

The slot antenna plate 203 has, for example, a thin plate shape, inparticular, a disc shape. The slot antenna plate 203 is formed with aplurality of microwave transmission slots 203 c and a plurality ofmicrowave transmission slots 203 b. It is preferable that each of theopposite surfaces of the slot antenna plate 203 in the plate thicknessdirection is flat. The plurality of microwave transmission slots 203 care formed on an inner periphery side of the slot antenna plate 203 andthe plurality of microwave transmission slots 203 b are formed on anouter periphery side of the slot antenna plate 203. The microwavetransmission slots 203 b, 203 c are formed through the slot antennaplate 203 in the plate thickness direction. Each of the plurality ofmicrowave transmission slots 203 c includes two slots 203 f, 203 g whichare elongated holes extending to intersect or cross at right angles eachother. Each of the plurality of microwave transmission slots 203 bincludes two slots 203 d, 203 e which are elongated holes extending tointersect or cross at right angles each other. The plurality ofmicrowave transmission slots 203 c are arranged at predeterminedintervals in the circumferential direction of the inner periphery side,and the plurality of microwave transmission slots 203 b are arranged atpredetermined intervals in the circumferential direction of the outerperiphery side.

In other words, the plurality of microwave transmission slots 203 cbecomes an inner slot group 203 c-1 which is formed by a plurality ofslot pairs 203 f, 203 g arranged along the circumferential direction ofthe slot antenna plate 203. In addition, the plurality of microwavetransmission slots 203 b becomes an outer slot group 203 b-1 which ispositioned outside the inner slot group 203 c-1 in the radial directionof the slot antenna plate 203 and formed by a plurality of slot pairs203 d, 203 e arranged along the circumferential direction of the slotantenna plate 203.

The inner slot group 203 c-1 transmits microwaves guided to the centerside of the dielectric window 300 by an inner waveguide to be describedlater, and the outer slot group 203 b-1 transmits microwaves guided tothe peripheral edge side of the dielectric window 300 by an outerwaveguide to be described later.

FIG. 7 is a cross-sectional view illustrating an example of a detailedconfiguration of the slot antenna in the first exemplary embodiment.FIGS. 8 and 9 are cross-sectional views illustrating portions of thecross-sectional view of the slot antenna illustrated in FIG. 7 in anenlarged scale. FIGS. 8 and 9 correspond to the portions surrounded by asolid line and a dotted line in FIG. 7, respectively. As illustrated inFIGS. 8 and 9, the slot antenna 200 includes a cooling plate 202, anintermediate metal body 208, a slot antenna plate 203, and a coaxialwaveguide 201.

As illustrated in FIGS. 7 to 9, the cooling plate 202 is installed to bespaced apart from an outer surface of an intermediate conductor 201 b ofthe coaxial waveguide 201 which will be described later. The coolingplate 202 includes a flow hole 202 c to circulate a coolant. The coolingplate 202 is used for cooling the intermediate metal body 208 and thedielectric window 300.

The intermediate metal body 208 is installed to be spaced apart from theprocessing container 100 side of the cooling plate 202. The intermediatemetal body 208 has a donut-shaped convex portion 208 f that separatesthe processing container 100 side surface of the intermediate metal body208 into a center side portion and an outer periphery side portion. Inaddition, it is preferable that the intermediate metal body 208 has auniform thickness. More specifically, it is preferable that thethickness of the intermediate metal body 208 is uniform, except for thearea where the convex portion 208 f is formed.

The slot antenna plate 203 is installed to be in contact with the convexportion 208 f on the processing container 100 side of the intermediatemetal body 208. On the processing container 100 side surface of the slotantenna plate 203, the slot antenna plate 203 includes, as slots forradiating microwaves, the microwave transmission slots 203 c formed in amore center side portion than the portion which is in contact with theconvex portion 208 f, and the microwave transmission slots 203 b formedin a more outer periphery side portion than the portion which is incontact with the convex portion 208 f.

The coaxial waveguide 201 is installed in a through hole whichcontinuously extends through the cooling plate 202 and the intermediatemetal body 208. In the example illustrated in FIG. 7, the processingcontainer 100 side end of the coaxial waveguide 201 is positioned withinthe through hole. The through hole is formed in the center side portiondefined by the convex portion 208 f on the intermediate metal body 208.

In addition, the coaxial waveguide 201 includes an inner conductor 201a, an intermediate conductor 201 b, and an outer conductor 201 c. Eachof the inner conductor 201 a, the intermediate conductor 201 b, and theouter conductor 201 c has a cylindrical shape, and may be installed suchthat the diametric centers thereof conform to each other. The innerconductor 201 a and the intermediate conductor 201 b are installed suchthat the outer surface of the inner conductor 201 a and the innersurface of the intermediate conductor 201 b are spaced apart from eachother. In addition, the intermediate conductor 201 b and the outerconductor 201 c are installed such that the outer surface of theintermediate conductor 201 b and the inner surface of the outerconductor 201 c are spaced apart from each other.

A mode converter 215 is connected to one waveguide 612 of the twowaveguides which are the microwave distribution targets of thedistributor 500 and connected to a space between the inner conductor 201a and the intermediate conductor 201 b installed in a hollow portion ofan intermediate conductor 201 b. The mode converter 215 converts a modeof the microwaves transmitted from the waveguide 612 and supplies themicrowaves after the mode conversion to the space between the innerconductor 201 a and the intermediate conductor 201 b.

A mode converter 216 is connected to the other waveguide 613 of the twowaveguides which are the microwave distribution targets of thedistributor 500 and connected to a space between the intermediateconductor 201 b and an outer conductor 201 c installed in a hollowportion of the outer conductor 201 c. The mode converter 216 convertsthe mode of the microwave transmitted from the waveguide 613 andsupplies the microwave after the mode conversion to the space betweenthe intermediate conductor 201 b and the outer conductor 201 c.

Here, in the coaxial waveguide 201, the hollow portion of the innerconductor 201 a forms a supply path that supplies the processing gasintroduced into the gas supply hole 204 to the gas inlet hole 207. Inaddition, in the coaxial waveguide 201, microwaves from each of thewaveguides 612, 623 are transmitted by each of a space between the innerconductor 201 a installed in the hollow portion of the intermediateconductor 201 b and the intermediate conductor 201 b, and a spacebetween the intermediate conductor 201 b installed in the hollow portionof the outer conductor 201 c and the outer conductor 201 c. That is, themicrowaves are transmitted by each of the hollow portion formed by theouter surface of the inner conductor 201 a and the inner surface of theintermediate conductor 201 b, and the hollow portion formed by the outersurface of the intermediate conductor 201 b and the inner surface of theouter conductor 201 c.

A first member 213 and a second member 214 are installed at an end ofthe coaxial waveguide 201. For example, the first member 213 isinstalled at a processing container 100 side end of the inner conductor201 a of the coaxial waveguide 201. The first member 213 including athrough hole has a first stepped portion 213 a protruding to a centerside space positioned at the more center side than the convex portion208 f in the space between the slot antenna plate 203 and theintermediate metal body 208. The length of the diameter of the firstmember 213 at the first stepped portion 213 a is equal to or smallerthan the inner diameter of the intermediate conductor 201 b. Inaddition, in the example illustrated in FIG. 9, the first member 213 isfixed to the gas supply hole 204.

In addition, for example, the second member 214 is installed at theprocessing container 100 side end of the intermediate conductor 201 b ofthe coaxial waveguide 201. The second member 214 including a throughhole has a third stepped portion 214 a protruding to the space betweenthe intermediate metal body 208 and the cooling plate 202. The length ofthe diameter of the second member 214 at the third stepped portion 214 ais equal to or smaller than the inner diameter of the outer conductor201 c. In addition, in the example illustrated in FIG. 9, the secondmember 214 is fixed to the intermediate metal body 208.

As illustrated in FIG. 9, each of the first member 213 and the secondmember 214 has a stepped shape rather than a tapered shape. In addition,the first member 213 is installed to be spaced apart from theintermediate metal body 208, and the second member 214 is installed tobe spaced apart from the cooling plate 202.

An example of a relationship of the through holes, the coaxial waveguide201, the first member 213, and the second member 214 will beadditionally described. In the example illustrated in FIG. 9, the innerconductor 201 a of the coaxial waveguide 201 extends through the throughhole formed in the cooling plate 202. In addition, the end of theintermediate conductor 201 b is positioned inside the through hole ofthe cooling plate 202, and the second member 214 is installed at the endof the intermediate conductor 201 b. In addition, the end of the outerconductor 201 c of the coaxial waveguide 201 is fixed to the coolingplate 202.

In addition, in the example illustrated in FIG. 9, the end of the innerconductor 201 a of the coaxial waveguide 201 is positioned inside thethrough hole of the intermediate metal body 208, and the first member213 is installed at the end of the inner conductor 201 a. In addition, agap exists between the intermediate conductor 201 b of the coaxialwaveguide 201 and the side surface 202 b of the through hole of thecooling plate 202, a gap exists between the inner conductor 201 a of thecoaxial waveguide 201 and the side surface 208 c of the through hole ofthe intermediate metal body 208, and each of the gaps forms a portion ofa waveguide that transmits microwaves.

FIG. 10 is a perspective view illustrating an example of theintermediate metal body in the first exemplary embodiment which isviewed from the dielectric window side. FIG. 11 is a perspective viewillustrating an example of the intermediate metal body in the firstexemplary embodiment which is viewed from the cooling plate side.

Here, the intermediate metal body 208 will be further described withreference to FIGS. 10 and 11. As illustrated in FIG. 108, theintermediate metal body 208 includes a donut-shaped convex portion 208f. As a result, the intermediate metal body 208 is in contact with theslot antenna plate 203 on the donut-shaped convex portion 208 f. Inother words, the donut-shaped convex portion 208 f of the intermediatemetal body 208 is formed on the top surface of the slot antenna plate203.

Here, in the intermediate metal body 208, a center side space is formedbetween the bottom surface 208 d of the intermediate metal body 208 andthe top surface 203 a of the slot antenna plate 203 in a range from thecenter side of the intermediate metal body 208 to the donut-shapedconvex portion 208 f. In the example illustrated in FIG. 7, the centerside space corresponds to a space where an inner slow-wave plate 209 tobe described later is installed and an empty space 211. In addition, inthe intermediate metal body 208, an outer periphery side space is formedbetween the bottom surface 208 e of the intermediate metal body 208 andthe top surface 203 a of the slot antenna plate 203 in a range from theouter periphery of the intermediate metal body 208 to the donut-shapedconvex portion 208 f of the intermediate metal body 208. In the exampleillustrated in FIG. 7, the outer periphery side space corresponds to aspace where an outer slow-wave plate 210 b to be described later isinstalled.

In addition, as illustrated in FIG. 11, the intermediate metal body 208includes a cooling plate 202 and one or plural convex portions 208 g.Here, the intermediate metal body 208 is in contact with the coolingplate 202 in the one or plural convex portions 208 g. In other words,the cooling plate 202 is installed on the one or plural convex portions208 g of the intermediate metal body 208. That is, the intermediatemetal body 208 and the cooling plate 202 are installed such that theouter surface of the intermediate metal body 208 and the cooling plate202 are spaced apart from each other, except for the one or pluralconvex portions 208 g. In other words, the bottom surface 202 a of thecooling plate and the top surface 208 a and the side surface 208 b ofthe intermediate metal body 208 are spaced apart from each other, exceptfor the one or plural convex portions 208 g.

Here, the cooling plate 202 has a convex portion 202 d protruding to thespace between the intermediate metal body 208 and the cooling plate 202.The convex portion 202 d is not in contact with the intermediate metalbody 208.

In addition, the intermediate metal body 208 and the cooling plate 202are in contact with each other through the one or plural convex portions208 g formed on the intermediate metal body 208. In other words, theintermediate metal body 208 and the cooling plate 202 are installed tobe spaced apart from each other, except for the one or plural convexportions 208 g of the intermediate metal body 208. Meanwhile, theintermediate metal body 208 is formed with a flow hole connected to theflow holes 202 c of the cooling plate 202 through the one or pluralconvex portions 208 g where the cooling plate 202 and the intermediatemetal body 208 are in contact with each other, thereby enhancing thecooling performance of the intermediate metal body 208. In addition, itis preferable that the one or plural convex portions 208 g are formed atan area where the outer slow-wave plate 210 is not installed.

In addition, the slot antenna 200 is provided with a slow-wave plate ata portion on the outer surface of the intermediate metal body 208.Specifically, the slot antenna 200 is provided with an inner slow-waveplate 209 and an outer slow-wave plate 210.

FIG. 12 is a view illustrating a processing gas supply path and amicrowave waveguide installed in the slot antenna in the first exemplaryembodiment. In FIG. 12, arrow 301 represents the processing gas supplypath formed in the slot antenna 200, arrow 302 represents the waveguideof microwaves supplied to an inner slot group 203 c-1 installed on theinner periphery side of the slot antenna plate 203, and arrow 303represents a waveguide of microwaves supplied to an outer slot group 203b-1 installed on the outer periphery side of the slot antenna plate 203.

As indicated in an arrow 301 of FIG. 12, in the slot antenna 200, whenthe processing gas is supplied to the gas inlet hole 207 from theprocessing gas supply source (not illustrated), the processing gas issupplied to the inside of the processing container 100 from the gassupply hole 204 through a hollow portion of the inner conductor 201 athat extends through the cooling plate 202 and the intermediate metalbody 208.

In addition, as indicated by arrow 302 in FIG. 12, the slot antenna 200includes an inner waveguide which is a waveguide that transmitsmicrowaves to the microwave transmission slots 203 c (inner slot group203 c-1) by transmitting the microwaves to the center side space, whichis positioned at the more center side than the convex portion 208 f inthe space between the slot antenna plate 203 and the intermediate metalbody 208, through the space between the inner conductor 201 a and theintermediate conductor 201 b. In addition, the inner waveguide isprovided with an inner slow-wave plate 209 above the microwavetransmission slots 203 c (inner slot group 203 c-1).

That is, in the inner waveguide, the microwaves supplied from thewaveguide 612 sequentially pass through the hollow portion formed by theouter surface of the inner conductor 201 a and the inner surface of theintermediate conductor 201 b, the hollow portion formed by the outersurface of the inner conductor 201 a and the side surface 208 c of thethrough hole formed in the intermediate metal body 208, the spacebetween the first member 213 and the intermediate metal body 208, theempty space 212 formed by the bottom surface of the intermediate metalbody 208 and the top surface of the slot antenna plate 203, and theinner slow-wave plate 209, and then, the microwaves are discharged tothe center side of the dielectric window 300 from the microwavetransmission slots 203 c (inner slot group 203 c-1).

In addition, as indicated by arrow 303 in FIG. 12, the slot antenna 200includes an outer waveguide which is a waveguide that transmitsmicrowaves to the microwave transmission slots 203 b (outer slot group203 b-1) by transmitting the microwaves to the outer periphery sidespace positioned at the more outer periphery side than the convexportion 208 f in the space between the slot antenna plate 203 and theintermediate metal body 208 sequentially through the space between theintermediate conductor 201 b and the outer conductor 201 c and the spacebetween the intermediate metal body 208 and the cooling plate 202. Theouter waveguide is provided with an outer slow-wave plate 210 above themicrowave transmission slots 203 b (outer slot group 203 b-1). Inaddition, the inner waveguide and the outer waveguide are notcommunicated with each other

That is, in the outer waveguide, the microwaves supplied from thewaveguide 613 sequentially pass through the hollow portion formed by theouter surface of the intermediate conductor 201 b and the inner surfaceof the outer conductor 201 c, the hollow portion formed by the outersurface of the intermediate conductor 201 b and the side surface 202 bof the cooling plate 202, the space between the second member 214 andthe cooling plate 202, the empty space 211 formed by the top surface 208a of the intermediate metal body 208 and the bottom surface 202 a of thecooling plate 202, the outer slow-wave plate 210 a, and the outerslow-wave plate 210 b, and then, the microwaves are discharged to theperiphery edge side of the dielectric window 300 from the microwavetransmission slots 203 b (outer slot group 203 b-1).

When the inner waveguide and the outer waveguide are not communicatedwith each other as described above, the interference of the microwavesbetween the inner waveguide and the outer waveguide may be avoided.

Meanwhile, although the first exemplary embodiment illustrates anexample in which the inner waveguide and the outer waveguide are notcommunicated with each other, the present disclosure is not limitedthereto. The inner waveguide and the outer waveguide may be communicatedwith each other through a through hole which does not transmitmicrowaves.

FIG. 13 is a perspective view illustrating a relationship of theintermediate metal body, the inner slow-wave plate, and the outerslow-wave plate in the first exemplary embodiment which is viewed fromthe dielectric window side. FIG. 14 is a perspective view illustrating arelationship of the intermediate metal body, the inner slow-wave plate,and the outer slow-wave plate in the first exemplary embodiment which isviewed from the cooling plate side.

As illustrated FIGS. 11 and 12, the inner slow-wave plate 209 isinstalled in a portion of or all over the center side space includingthe upper portion of the microwave transmission slots 203 c. Inaddition, the inner slow-wave plate 209 has an inclination or step on aninterface between the inner slow-wave plate 209 and the empty space 211in which the inner slow-wave plate 209 is not provided, preferably inthe center side space.

That is, as illustrated in FIGS. 7 to 14, the inner slow-wave plate 209is installed over a predetermined length toward the inner periphery sidefrom the convex portion 208 f of the intermediate metal body 208 to fillthe space formed between the bottom surface 208 d of the intermediatemetal body 208 and the top surface 203 a of the slot antenna plate 203.As a result, in the portion existing in the inner periphery side fromthe convex portion 208 f of the intermediate metal body 208 in the spaceformed between the bottom surface 208 d of the intermediate metal body208 and the top surface 203 a of the slot antenna plate 203, the innerslow-wave plate 209 is installed in a predetermined length range fromthe convex portion 208 f of the intermediate metal body 208, and theempty space 211 is formed from the through hole of the intermediatemetal body 208 to the portion where the inner slow-wave plate 209 isinstalled. In addition, the inner slow-wave plate 209 has preferably aninclined shape in the interface with the space 211.

As illustrated in FIGS. 13 and 14, the outer slow-wave plate 210 isinstalled to be continued in the outer periphery side space and aportion of the space between the intermediate metal body 208 and thecooling plate 202. For example, the outer slow-wave plate 210 includes afirst outer slow-wave plate 210 b installed in the outer periphery sidespace, and a second outer slow-wave plate 210 a installed to becontinued from an end of the first outer slow-wave plate 210 b andinstalled in a portion of the space between the intermediate metal body208 and the cooling plate 202.

That is, as illustrated in FIGS. 7 to 14, the outer slow-wave plate 210b is installed to fill the space formed between the bottom surface 208 eof the intermediate metal body 208 and the top surface 203 a of the slotantenna plate 203. In addition, the outer slow-wave plate 210 a isinstalled over a predetermined length from the end of the outerslow-wave plate 210 b to fill the space formed between the bottomsurface 202 a of the cooling plate 202 and the top surface 208 a and theside surface 208 b of the intermediate metal body 208.

In addition, the outer slow-wave plate 210 a is installed to apredetermined length range from the outer periphery of the intermediatemetal body 208 on the top surface 208 a of the intermediate metal body208. As a result, in the space formed between the top surface 208 a ofthe intermediate metal body 208 and the bottom surface 202 a of thecooling plate 202, an empty space 212 is formed from the through hole ofthe intermediate metal body 208 to the portion where the outer slow-waveplate 210 a is installed. The one or plural convex portions 208 g wherethe cooling plate 202 and the intermediate metal body 208 are in contactwith each other are formed in the empty space 212 from the through holeof the intermediate metal body 208 to the portion where the outerslow-wave plate 210 a is installed. In addition, the outer slow-waveplate 210 has a second stepped portion 210 ab protruding toward thecenter side in the interface between the outer slow-wave plate 210 andthe portion where the outer slow-wave plate 210 is not installed in thespace between the intermediate metal body 208 and the cooling plate 202.Preferably, the length of the outer slow-wave plate 210 installed in theinner waveguide is longer than the length of the inner slow-wave plate209 installed in the outer waveguide.

Descriptions will be described on a relationship between the outerwaveguide, and the one or plural convex portions 208 g formed on theintermediate metal body 208. As described above, the intermediate metalbody 208 and the cooling plate 202 are in contact with each other in theone or plural convex portions 208 g formed on the intermediate metalbody 208. Here, the one or plural convex portions 208 g are formed inthe empty space 211. In other words, the one or plural convex portions208 g are not enclosed by the outer slow-wave plate 210.

Subsequently, a plasma supplying method using the microwave plasmaprocessing apparatus 10 illustrated in FIG. 1 will be described. FIG. 15is a flowchart illustrating an example of a flow of a plasma supplyingmethod according to the first exemplary embodiment.

As illustrated in FIG. 15, the monitor unit 704 monitors the voltage ofeach of the two waveguides 612, 613, using the voltage sensors 622, 623installed in two waveguides 612, 613, respectively (step S101). Monitorvalues of voltage monitored by the monitor unit 704 may include, forexample, Vpp which is a peak to peak value of voltage, and Vdc which isan intermediate value of voltage may be used. Referring to Vpp as anexample, the monitor unit 704 detects the Vpp value as the monitorvalue.

The control unit 708 acquires a monitor value obtained through amonitoring by the monitor unit 704 (step S102). In addition, the controlunit 708 calculates a monitor difference which is a difference betweenthe acquired monitor value and a reference value (step S103). Inaddition, the control unit 708 acquires, from the storage unit 702, acontrol value of a distribution ratio corresponding to the calculatedmonitor difference (step S104). In addition, the control unit 708executes a control of a distribution ratio of the distributor 500 basedon the control value of the distribution ratio acquired from the storageunit 702 (step S105). For example, the control unit 708 acquires the Vppvalue from the monitor unit 704 to calculate a monitor difference “D1”which is a difference between the acquired Vpp value and a referencevalue and acquires, from the storage unit 702, a control value “C1”corresponding to the calculated monitor difference from the storage unit702 and output the acquired control value to the distributor 500. Atthis time, the distributor 500 distributes microwaves input from thewaveguide 602 to two waveguides 612, 613, using the acquired controlvalue.

Using the acquired monitor value, the control unit 708 controls a shiftamount of the phase shifter 706 so that a phase of the voltage of thewaveguide 612 and a phase of the voltage of the waveguide 613 becomeproper phases (step S106). The appropriate phases refer to phasesinverted to offset microwaves transmitted to the center side and theperipheral edge side of the dielectric window 300.

When the processing is ended (step S107, Yes), the control unit 708terminates the execution of the plasma supply processing. Meanwhile,when the processing is not ended (step S107, No), the control unit 708monitors the voltage of each of the two waveguides 612, 613 again (stepS108). In addition, the control unit 708 determines whether there is achange in the monitor values (step S109). When there is a change in themonitor values (step S109, Yes), the control unit 708 executes theprocessing subsequent to step S103 so as to dynamically optimize thedistribution ratio. Meanwhile, when there is no change in the monitorvalues (step S109, No), the control unit 708 returns the processing tostep S107.

As described above, the microwave plasma processing apparatus 10 of thefirst exemplary embodiment includes a distributor configured todistribute microwaves to two waveguides connected to the inner waveguideand the outer waveguide of the slot antenna 200 and acquires, from astorage unit, a control value of the distributor corresponding to themonitor values of the voltages of the two waveguides, and controls thedistribution ratio of the distributor using the acquired control value.Due to this, the microwave plasma processing apparatus 10 mayindividually radiate the microwaves from the inner slot group and theouter slot group of the slot antenna 200 to the processing space S whiledistributing the microwaves to the inner waveguide and the outerwaveguide of the slot antenna 200 at an optimal distribution ratio. As aresult, the microwave plasma processing apparatus 10 may maintaindistribution uniformity of plasma excited by the microwaves in theprocessing space S in the processing container.

The microwave plasma processing apparatus 10 of the first exemplaryembodiment shifts the phase of one waveguide using the monitor values ofthe voltages of the two waveguides connected to the inner waveguide andthe outer waveguide of the slot antenna 200, so that the phases of thevoltages of the two waveguides become appropriate phases to each other.Due to this, the microwave plasma processing apparatus 10 may suppressthe interference of the microwaves guided to the dielectric window 300from two waveguides connected to the inner waveguide and the outerwaveguide of the slot antenna 200 through the inner waveguide and theouter waveguide of the slot antenna 200 by inverting the phases of themicrowaves in the dielectric window below the antenna. As a result, themicrowave plasma processing apparatus 10 may more appropriately maintaindistribution uniformity of plasma excited by the microwaves in theprocessing space S in the processing container.

In the first exemplary embodiment, the tuner 608 matches impedance atthe microwave generator 500 side and impedance at the slot antenna 200side. As a result, the microwave plasma processing apparatus 10 may moreappropriately maintain distribution uniformity of plasma excited by themicrowave in the processing space S in the processing container.

Modified Example 1

Subsequently, Modified Example 1 of the microwave plasma processingapparatus according to the first exemplary embodiment will be described.FIG. 16 is a diagram illustrating an example of an externalconfiguration of Modified example 1 of the microwave plasma processingapparatus according to the first exemplary embodiment. The microwaveplasma processing apparatus 10 a according to Modified Example 1 isdifferent from the microwave plasma processing apparatus 10 illustratedin FIG. 1 in that a plurality of sets of processing containers and slotantennas are provided and the distributor 500 distributes microwaves toa plurality of waveguides which correspond to the plurality of sets ofprocessing containers and slot antennas, respectively. Therefore, inFIG. 16, descriptions on the same configuration as the microwave plasmaprocessing apparatus 10 illustrated in FIG. 1 will be omitted.

As illustrated in FIG. 16, the microwave plasma processing apparatus 10a according to Modified Example 1 includes a plurality of sets ofprocessing containers 100 a and slot antennas 200 a instead of theprocessing container 100 and the slot antenna 200 illustrated in FIG. 1.In Modified Example 1, the microwave plasma processing apparatus 10 aincludes two sets of processing containers 100 a and slot antennas 200a.

The distributor 500 distributes microwaves to the plurality ofwaveguides corresponding to the plurality of sets of processingcontainers 100 a and slot antennas 200 a, respectively. In ModifiedExample 1, the distributor 500 distributes the microwaves to the twowaveguides 612, 613 corresponding to two sets of processing containers100 and slot antennas 200 a, respectively.

The slot antenna 200 a has one waveguide connected to the waveguide 612or the waveguide 613 therein. The slot antenna 200 a transmits themicrowaves distributed to two respective waveguides 612, 613 by thedistributor 500 to the dielectric window 300 through the inner waveguideand radiates the transmitted microwaves to the processing space S of theprocessing container 100 a combined with the slot antenna 200 a.

The control unit 708 acquires, from the monitor unit 704, the monitorvalue of the voltage of each of the two waveguides 612, 613 which ismonitored by the monitor unit 704. Then, the control unit 708 calculatesa monitor difference which is a difference between the monitor value andthe reference value of the voltage of each of the two waveguides 612,613. In addition, the control unit 708 acquires, from the storage unit702, a control value of a distribution ratio of the distributor 500corresponding to the calculated monitor difference and controls thedistribution ratio of the distributor 500 based on the acquired controlvalue.

For example, it is assumed that the storage unit 702 stores a monitordifference “D1” and a control value “1:1” to correspond to each other.In this case, the control unit 708 acquires, from the storage unit 702,the control value “1:1” of the distribution ratio of the distributor 500corresponding to the monitor difference, and outputs the acquiredcontrol value to the distributor 500. As a result, the distributor 500distributes the microwaves input from the waveguide 602 to the twowaveguides 612, 613, using the acquired control value “1:1”. 50% of themicrowaves distributed to the waveguide 612 are radiated to theprocessing space S in the processing container 100 a from the slotantenna 200 a corresponding to one set of the two sets of processingcontainers 100 a and slot antennas 200 a. The 50% of microwavesdistributed to the waveguide 613 are radiated to the processing space Sin the processing container 100 a from the slot antenna 200 acorresponding to the other set of the two sets of processing containers100 a and slot antennas 200 a.

The microwave plasma processing apparatus 10 a of Modified Example 1 mayindividually radiate the microwaves from each slot antenna to theprocessing space S of each processing container while distributing themicrowaves to the two waveguides which correspond to the two sets ofprocessing containers and slot antennas, respectively, at an optimaldistribution ratio. As a result, the microwave plasma processingapparatus 10 a may maintain plasma excited by the microwave in a uniformstate in the processing space S of the processing container. Further,since the microwave plasma processing apparatus 10 a may supplymicrowaves generated by one microwave generator to the plurality ofprocessing containers simultaneously, the increase of the scale of theapparatus may be suppressed.

Modified Example 2

Subsequently, Modified Example 2 of the microwave plasma processingapparatus according to the first exemplary embodiment will be described.FIG. 17 is a diagram illustrating an example of an externalconfiguration of Modified Example 2 of the microwave plasma processingapparatus according to the first exemplary embodiment. The microwaveplasma processing apparatus 10 b according to Modified Example 2 isdifferent from the microwave plasma processing apparatus 10 illustratedin FIG. 1 in that a plurality of sets of processing containers and slotantennas are provided and a plurality of distributors are provided.Therefore, in FIG. 17, descriptions on the same configuration as themicrowave plasma processing apparatus 10 illustrated in FIG. 1 will beomitted.

As illustrated in FIG. 17, the microwave plasma processing apparatus 10b according to Modified Example 2 includes a plurality of sets ofprocessing containers 100 b and slot antennas 200 b instead of theprocessing container 100 and the slot antenna 200 illustrated in FIG. 1.In Modified Example 2, the microwave plasma processing apparatus 10 bincludes three sets of processing containers 100 b and slot antennas 200b.

The microwave plasma processing apparatus 10 b of Modified Example 2includes a plurality of distributors. In Modified Example 2, themicrowave plasma processing apparatus 10 b includes two distributors 500a and 500 b. The two distributors 500 a and 500 b distribute microwavesinput from the waveguide 602 to a plurality of waveguides stepwisesequentially. That is, the distributor 500 a distributes the microwavesinput from the waveguide 602 to the two waveguides 612, 613. One sidemicrowaves distributed to the waveguide 612 by the distributor 500 a aresupplied to any one set of three sets of processing containers 100 b andslot antennas 200 b. The other side microwaves distributed to thewaveguide 613 by the distributor 500 a are supplied to the distributor500 b. The distributor 500 b distributes the microwaves input from thedistributor 500 a through the waveguide 613 to the two waveguides 614,615. One side microwaves distributed to the waveguide 614 by thedistributor 500 b are supplied to any one set of three sets ofprocessing containers 100 b and slot antennas 200 b. The other sidemicrowaves distributed to the waveguide 615 by the distributor 500 b aresupplied to any one set of the three sets of processing containers 100 band slot antennas 200 b.

The slot antenna 200 b has one waveguide connected to the waveguide 612,the waveguide 614, or the waveguide 615 therein. The slot antenna 200 btransmits the microwaves distributed to the waveguide 612, the waveguide614, or the waveguide 615 to the dielectric window 300 through theinternal waveguide and radiates the transmitted microwaves to theprocessing space S of the processing container 100 b combined with theslot antenna 200 b.

For each distributor, the storage unit 702 stores a monitor differencewhich is a difference between a monitor value of the voltage of each oftwo waveguides which are microwave distribution targets and apredetermined voltage reference value, and a control value of thedistribution ratio of the distributor corresponding to the monitordifference such that the monitor difference and the control valuecorrespond to each other. For example, the storage unit 702 stores amonitor difference “D1” and a control value “1:2 (=waveguide612:waveguide 613)” to correspond to each other, for the distributor 500a. Further, for example, the storage unit 702 stores a monitordifference “D1” and a control value “1:1 (=waveguide 614:waveguide 615)”to correspond to each other, for the distributor 500 b.

The monitor unit 704 monitors the voltage of each of the waveguides 612,614, 615 by using voltage sensors 622, 623 a, 623 b, which are installedin the waveguides 612, 614, 615, respectively, and output the monitorvalues to the control unit 708.

The control unit 708 individually controls a distribution ratio of eachof a plurality of distributors based on the control values acquired fromthe storage unit 702. In detail, the control unit 708 acquires, from themonitor unit 704, a monitor value of the voltage of each of thewaveguides 612, 614, 615 which is monitored by the monitor unit 704. Inaddition, the control unit 708 calculates a monitor difference which isa difference between the monitor value and the reference value of thevoltage of each of the waveguides 612, 614, 615. In addition, thecontrol unit 708 acquires, from the storage unit 702, the control valueof the distribution ratio of the distributor corresponding to thecalculated monitor difference and individually controls the distributionratio of each of the plurality of distributors based on the acquiredcontrol value.

For example, it is assumed that the storage unit 702 stores a monitordifference “D1” and a control value “1:2 (=waveguide 612:waveguide 613)”to correspond to each other, for the distributor 500 a, and stores amonitor difference “D1” and a control value “1:1 (=waveguide614:waveguide 615)” to correspond to each other, for the distributor 500b. In this case, the control unit 708 acquires, from the storage unit702, the control value “1:2 (=waveguide 612:waveguide 613)” of thedistribution ratio of the distributor 500 a corresponding to the monitordifference and outputs the acquired control value to the distributor 500a. Further, the control unit 708 acquires, from the storage unit 702,the control value “1:1 (=waveguide 614:waveguide 615)” of thedistribution ratio of the distributor 500 b corresponding to the monitordifference and outputs the acquired control value to the distributor 500b. As a result, the distributor 500 a distributes the microwaves inputfrom the waveguide 602 to the two waveguides 612, 613, using theacquired control value “1:2 (=waveguide 612:waveguide 613)”. 33.3% ofthe microwaves distributed to the waveguide 612 are radiated to theprocessing space S in the processing container 100 b from the slotantenna 200 b corresponding to one set of the three sets of processingcontainers 100 b and slot antennas 200 b. 66.6% of the microwavesdistributed to the waveguide 613 are supplied to the distributor 500 b.The distributor 500 b distributes the microwaves input from thedistributor 500 a through the waveguide 613 to the two waveguides 614,615, using the acquired control value “1:1 (=waveguide 614:waveguide615)”. 50% of the microwaves distributed to the waveguide 614 areradiated to the processing space S in the processing container 100 bfrom the slot antenna 200 b corresponding to one set of the three setsof processing containers 100 b and slot antennas 200 b. 50% of themicrowaves distributed to the waveguide 615 are radiated to theprocessing space S in the processing container 100 b from the slotantenna 200 b corresponding to the one set of the three sets ofprocessing containers 100 b and slot antennas 200 b.

The microwave plasma processing apparatus 10 b of Modified Example 2 mayindividually radiate microwaves to the processing space S of eachprocessing container from each slot antenna while distributing themicrowaves to three waveguides, which correspond to three sets ofprocessing containers and the slot antennas, respectively, at an optimaldistribution ratio. As a result, the microwave plasma processingapparatus 10 b may maintain plasma excited by the microwave in a uniformstate in the processing space S in the processing container. Further,since the microwave plasma processing apparatus 10 b may supplymicrowaves generated by one microwave generator to the plurality ofprocessing containers simultaneously, the increase of the size of theapparatus may be suppressed.

Modified Example 3

Subsequently, Modified Example 3 of the microwave plasma processingapparatus according to the first exemplary embodiment will be described.FIG. 18 is a diagram illustrating an example of an externalconfiguration of Modified Example 3 of the microwave plasma processingapparatus according to the first exemplary embodiment. The microwaveplasma processing apparatus 10 c according to Modified Example 3 isdifferent from the microwave plasma processing apparatus 10 illustratedin FIG. 1 in that a plurality of sets of processing containers and slotantennas are provided and a plurality of distributors are provided.Therefore, in FIG. 18, descriptions on the same configuration as themicrowave plasma processing apparatus 10 illustrated in FIG. 1 will beomitted.

As illustrated in FIG. 18, the microwave plasma processing apparatus 10c according to Modified Example 3 includes a plurality of sets ofprocessing containers 100 c and slot antennas 200 c instead of theprocessing container 100 and the slot antenna 200 illustrated in FIG. 1.In Modified Example 3, the microwave plasma processing apparatus 10 cincludes four sets of processing containers 100 c and slot antennas 200c.

The microwave plasma processing apparatus 10 c of Modified Example 3includes a plurality of distributors. In Modified Example 3, themicrowave plasma processing apparatus 10 c includes three distributors500 a, 500 b, and 500 c. The three distributors 500 a, 500 b, and 500 cdistribute microwaves input from the waveguide 602 to a plurality ofwaveguides stepwise sequentially. That is, the distributor 500 adistributes the microwaves input from the waveguide 602 to twowaveguides 612, 613. One side microwaves distributed to the waveguide612 by the distributor 500 a are supplied to the distributor 500 c. Theother side microwaves distributed to the waveguide 613 by thedistributor 500 a are supplied to the distributor 500 b. The distributor500 b distributes the microwaves input from the distributor 500 athrough the waveguide 613 to two waveguides 614, 615. One sidemicrowaves distributed to the waveguide 614 by the distributor 500 b aresupplied to any one set of the four sets of processing containers 100 cand slot antennas 200 c. The other side microwaves distributed to thewaveguide 615 by the distributor 500 b are supplied to any one set ofthe four sets of processing containers 100 c and slot antennas 200 c.The distributor 500 c distributes the microwaves input from thedistributor 500 a through the waveguide 612 to two waveguides 616, 617.One side microwaves distributed to the waveguide 616 by the distributor500 c are supplied to any one set of the four sets of processingcontainers 100 c and slot antennas 200 c. The other side microwavesdistributed to the waveguide 617 by the distributor 500 c are suppliedto any one set of the four sets of processing containers 100 c and slotantennas 200 c.

The slot antenna 200 c has one waveguide connected to the waveguide 614,the waveguide 615, the waveguide 616, or the waveguide 617 therein. Theslot antenna 200 c transmits the microwaves distributed to the waveguide614, the waveguide 615, the waveguide 616, or the waveguide 617 to thedielectric window 300 through the internal waveguide and radiates thetransmitted microwaves to the processing space S of the processingcontainer 100 c combined with the slot antenna 200 c.

For each distributor, the storage unit 702 stores a monitor differencewhich is a difference between a monitor value of the voltage of each oftwo waveguides which are microwave distribution targets and apredetermined voltage reference value, and a control value of thedistribution ratio of the distributor corresponding to the monitor valuesuch that the monitor difference and the control value correspond toeach other. For example, the storage unit 702 stores a monitordifference “D1” and a control value “1:1 (=waveguide 612:waveguide 613)”to correspond to each other, for the distributor 500 a. Further, forexample, the storage unit 702 stores the monitor difference “D1” and acontrol value “1:1 (=waveguide 614:waveguide 615)” to correspond to eachother, for the distributor 500 b. Further, for example, the storage unit702 stores a monitor difference “D1” and a control value “1:1(=waveguide 616:waveguide 617)” to correspond to each other, for thedistributor 500 c.

The monitor unit 704 monitors a voltage of each of the waveguides 614,615, 616, 617, using voltage sensors 623 a, 623 b, 622 a, 622 b whichare installed in the waveguides 614, 615, 616, 617, respectively, andoutputs the monitor value to the control unit 708.

The control unit 708 individually controls the distribution ratio ofeach of the plurality of distributors based on the control valuesacquired from the storage unit 702. Specifically, the control unit 708acquires, from the monitor unit 704, a monitor value of the voltage ofeach of the waveguides 614, 615, 616, 617 which is monitored by themonitor unit 704. In addition, the control unit 708 calculates a monitordifference which is a difference between the monitor value and thereference value of the voltage of each of the waveguides 614, 615, 616,617. In addition, the control unit 708 acquires, from the storage unit702, the control value of the distribution ratio of the distributorcorresponding to the calculated monitor difference and individuallycontrols the distribution ratio of each of the plurality of distributorsbased on the acquired control value.

For example, it is assumed that the storage unit 702 stores a monitordifference “D1” and a control value “1:1 (=waveguide 612:waveguide 613)”to correspond to each other, for the distributor 500 a, stores a monitordifference “D1” and the control value “1:1 (=waveguide 614:waveguide615)” to correspond to each other, for respect to the distributor 500 b,and stores a monitor difference “D2” and a control value “1:1(=waveguide 616:waveguide 617)” to correspond to each other, for thedistributor 500 c. In this case, the control unit 708 acquires, from thestorage unit 702, the control value “1:1 (=waveguide 612:waveguide 613)”of the distribution ratio of the distributor 500 a corresponding to themonitor difference and outputs the acquired control value to thedistributor 500 a. Further, the control unit 708 acquires, from thestorage unit 702, the control value “1:1 (=waveguide 614:waveguide 615)”of the distribution ratio of the distributor 500 b corresponding to themonitor difference and outputs the acquired control value to thedistributor 500 b. Further, the control unit 708 acquires, from thestorage unit 702, the control value “1:1 (=waveguide 616:waveguide 617)”of the distribution ratio of the distributor 500 c corresponding to themonitor difference and outputs the acquired control value to thedistributor 500 c. As a result, the distributor 500 a distributes themicrowaves input from the waveguide 602 to the two waveguides 612, 613,using the acquired control value “1:1 (=waveguide 612:waveguide 613)”.50% of the microwaves distributed to the waveguide 612 are supplied tothe distributor 500 c. 50% of the microwaves distributed to thewaveguide 613 are supplied to the distributor 500 b. The distributor 500b distributes the microwaves input from the distributor 500 a throughthe waveguide 613 to the two waveguides 614, 615, using the acquiredcontrol value “1:1 (=waveguide 614:waveguide 615)”. 50% of themicrowaves distributed to the waveguide 614 are radiated to theprocessing space S in the processing container 100 c from the slotantenna 200 c corresponding to one set of the four sets of processingcontainers 100 c and slot antennas 200 c. 50% of the microwavesdistributed to the waveguide 615 are radiated to the processing space Sin the processing container 100 c from the slot antenna 200 ccorresponding to one set of the four sets of processing containers 100 cand slot antennas 200 c. The distributor 500 c distributes microwavesinput from the distributor 500 a through the waveguide 616 to the twowaveguides 616, 617, using the acquired control value “1:1 (=waveguide616:waveguide 617)”. 50% of the microwaves distributed to the waveguide616 are radiated to the processing space S in the processing container100 c from the slot antenna 200 c corresponding to one set of the foursets of processing containers 100 c and slot antennas 200 c. 50% of themicrowaves distributed to the waveguide 617 are radiated to theprocessing space S in the processing container 100 c from the slotantenna 200 c corresponding to one set of four sets of processingcontainers 100 c and slot antennas 200 c.

The microwave plasma processing apparatus 10 c of Modified Example 3 mayindividually radiate microwaves to the processing space S of eachprocessing container from each slot antenna while distributing themicrowaves to four waveguides which correspond to four sets of theprocessing containers and the slot antennas, respectively, at an optimaldistribution ratio. As a result, the microwave plasma processingapparatus 10 c may maintain plasma excited by the microwaves in auniform state in the processing space S in the processing container.Further, since the microwave plasma processing apparatus 10 c may supplymicrowaves generated by one microwave generator to the plurality ofprocessing containers simultaneously, the increase of the size of theapparatus may be suppressed.

From the foregoing, it will be appreciated that various exemplaryembodiments of the present disclosure have been described herein forpurposes of illustration, and that various modifications may be madewithout departing from the scope and spirit of the present disclosure.Accordingly, the various exemplary embodiments disclosed herein are notintended to be limiting, with the true scope and spirit being indicatedby the following claims.

What is claimed is:
 1. A microwave plasma processing apparatuscomprising: a processing container configured to define a processingspace; a microwave generator configured to generate microwaves forgenerating plasma of a processing gas introduced into the processingspace; a distributor configured to distribute the microwaves to aplurality of waveguides; an antenna installed in the processingcontainer and to radiate the microwaves distributed to the plurality ofwaveguides by the distributor, to the processing space; a monitor unitconfigured to monitor a voltage of each of the plurality of waveguides;a storage unit configured to store a difference between a monitor valueof the voltage monitored by the monitor unit and a predeterminedreference value of the voltage and a control value of a distributionratio of the distributor corresponding to the difference; and a controlunit configured to acquire the control value of the distribution ratioof the distributor, which corresponds to the difference between themonitor value of the voltage monitored by the monitor unit and thepredetermined reference value of the voltage, from the storage unit andto control the distribution ratio of the distributor based on theacquired control value thereby distributing the microwaves to theplurality of waveguides of the antenna.
 2. The microwave plasmaprocessing apparatus of claim 1, further comprising: a phase shifterinstalled in a specific waveguide of at least one of the plurality ofwaveguides to shift a phase of a voltage of the specific waveguide by aset shift amount, wherein apart from the control of the distributionratio of the distributor, the control unit properly controls the phaseof the voltage of the specific waveguide and phases of voltages ofwaveguides other than the specific waveguide among the plurality ofwaveguides using the monitor value of the voltage monitored by themonitor unit so as to control the shift amount of the phase shifter suchthat the phases become inverse phases in a dielectric window below theantenna.
 3. The microwave plasma processing apparatus of claim 1,further comprising: a waveguide guiding the microwave generated by themicrowave generator to the distributor; and a tuner installed in thewaveguide to match impedance at the microwave generator side andimpedance of the antenna side.
 4. The microwave plasma processingapparatus of claim 1, wherein the microwave plasma processing apparatusis provided with a plurality of sets of processing containers and theantennas, the distributor distributes microwaves to the plurality ofwaveguides corresponding to the plurality of sets of processingcontainers and antennas, respectively, the antenna radiates themicrowaves distributed to each of the plurality of waveguides by thedistributor to the processing space of the processing container combinedwith the antenna, and the control unit controls the distribution ratioof the distributor based on the control value acquired from the storageunit.
 5. The microwave plasma processing apparatus of claim 1, whereinthe microwave plasma processing apparatus is provided with a pluralityof distributors, the plurality of distributors distribute the microwavesgenerated by the microwave generator to the plurality of waveguidesstepwise sequentially, the storage unit stores the difference and acontrol value of the distribution ratio of the distributor correspondingto the difference to correspond to each other, for each distributor, andthe control unit individually controls the distribution ratio of each ofthe plurality of distributors based on the control value acquired fromthe storage unit.
 6. A microwave supplying method using a microwaveplasma processing apparatus including a processing container configuredto defined a processing space, a microwave generator configured togenerate microwaves for generating plasma of a processing gas introducedinto the processing space, a distributor configured to distribute themicrowaves to a plurality of waveguides, and an antenna installed in theprocessing container and to radiating, to the processing space, themicrowaves distributed to the plurality of waveguides by thedistributor, the method comprising: monitoring a voltage of each of theplurality of waveguides; storing a difference between a monitor value ofthe voltage monitored by a monitor unit and a predetermined referencevalue of the voltage and a control value of a distribution ratio of thedistributor corresponding to the difference; acquiring the control valueof the distribution ratio of the distributor corresponding to thedifference between the monitor value of the monitored voltage and thepredetermined reference value of the voltage from the storage unit; andcontrolling the distribution ratio of the distributor based on thecontrol value acquired at the acquiring in order to distribute themicrowaves to the plurality of waveguides of the antenna.